According to this kind of invention in related arts, a three-dimensional shaped molding object including a number of sintered layers is manufactured by repeating a process of supplying powder material from powder supply equipment to form a powder layer and a process of radiating a light beam or an electron beam to a predetermined region of the powder layer formed in the mentioned process to sinter the powder in the predetermined region.
Meanwhile, in the above-described related arts, a galvano scanner device is used to radiate the light beam or the electron beam in most cases. For example, Patent Document 1 of JP 2005-336547 A discloses an invention in which a light beam or an electron beam emitted from a laser oscillator (20) is reflected on a single galvano scanner device (scanner 22), and further radiated to a powder layer by changing a reflecting direction thereof. With this configuration, there are effects that a radiated location of the light beam or the electron beam can be moved fast by the galvano scanner device, and there is an effect of shortening molding time.
However, to sinter the powder material, high-energy radiation is required and the light beam or the electron beam is needed to be concentrated. Normally, the light beam or the electron beam used for sintering is 200 W laser, and the light beam is concentrated until a radiation diameter becomes 0.1 mm or less so as to increase energy. Since the radiation diameter is extremely small as described above, there is a problem in that it takes an extremely long time to manufacture a relatively large molding object even in the case of using the galvano scanner device.
In general, a surface of the three-dimensional molding object is required to have high hardness and density, but in many cases, the inside thereof is allowed to have relatively low hardness and density. Therefore, according to the related art, to shorten the molding time, energy density is lowered by, for example, upsizing the radiation diameter at the time of sintering the powder layer located on an inner side of the molding object, and the energy density is raised by downsizing the radiation diameter only at the time of sintering the powder layer located on an outline side of the molding object.
However, according to this related art, control tends to be complicated because the radiation diameter is needed to be changed and there are number of scanning patterns executed by the single galvano scanner device.